1. Field of the Invention
The present invention relates to a paper guide device disposed in a folding drum and folding roller section in a folding machine of a rotary press.
2. Description of the Prior Art
FIGS. 3 and 4 illustrate a paper guide device in the prior art.
A multiple web W twice-folded by means of a triangular plate is led via nipping rollers to the nip between a cutting drum 1 and a folding drum 2 to be cut. Then the cut web is folded, by a folding blade 3 projecting from the folding drum 2 and by means of folding rollers 4a and 4b, and formed into a pull-out binder which is ejected below the folding rollers.
Paper guides 6 and 7 hold the cut web on the outer circumference of the folding drum 2 to eliminate the fluttering of the paper web when it is folded, and also to prevent the production of an unacceptable pull-out binder such as one having folded edges. While the width of a gap between each of the paper guides 6 and 7 and the folding drum 2 can be adjusted to an optimum value depending upon a number of completed pages, during normal operation the widths of the gaps, e.g. b.sub.1, is held fixed.
On the other hand, the gap between the folding rollers 4a and 4b has a width corresponding to the thickness of a number of completed pages of a pull-out binder, and they are operated while undergoing periodical minute movement. They can also move to positions where the gap f can insure the protection of the machine during an abnormal condition such as when clogged with paper. Accordingly, gaps c are respectively reserved between the folding roller 4a and the guide 7 such that even if the folding rollers 4a and 4b should move a distance f they will not come into contact with the paper guides 6 and 7, respectively. Therefore, the gaps c between the folding roller 4a and the paper guide 6 and between the folding roller 4b and the paper guide 7 during normal operation are chosen considerably broad. It is to be noted that reference numeral 5 designates a support shaft for the paper guide 6, numeral 12 designates a lever which is rotatable about a shaft 13, numeral 14 designates a flange mounted to the machine frame (not shown) and supporting shaft 13, numeral 15 designates a paper guide gap adjusting device, and numeral 8a designates an arm which is rotatable about a shaft 10a and supports the folding roller 4a.
With respect to the paper guide gap adjusting device 15, reference numeral 22 designates a shaft connected to a rotary actuator (motor or handle, e.g.), numeral 18 designates a threaded shaft connected directly to shaft 22 via a coupling 21, numeral 16 designates a base fixed to a frame of the machine (not shown), numerals 17 designate bearings mounted to base 16 and rotatably supporting shaft 18, numeral 19 designates a block internally threaded to shaft 18, numeral 19a designates a pin fixed to block 19a and located in a recess in lever 12, and numeral 20 designates a spring for damping vibrations of lever 12.
The gap b.sub.1 can be adjusted by rotating shaft 22. When shaft 22 rotates, the nut or block 19a is moved along threaded lever 12 about shaft 13.
When the cut web is continuously folded by means of the folding blade and the folding rollers, variations in the flow of air around the outer circumference of the folding drum during the folding operation are one factor which determines whether or not a regular pull-out binder will be produced. The paper guides prevent abnormal behavior of the web which would otherwise be caused by this air flow variation during the folding operation.
However, in the heretofore known paper guide device as described above, since the guides are not located proximate the folding rollers during operation, i.e. the gaps between the guides and the folding rollers are rather large, an abnormal behavior at a rear end portion of the web is brought about, and so problems arise in that defects, such as the folding of the edges of the pull-out binder and the like, occur.